Due to recent advances in digital signal processing and communications technology, radio and TV broadcast signals are provided gradually in the form of digital data. As signals are provided in the form of digital data, a variety of information is now allowed to be added to TV or radio broadcast signals, the information including news, stock, weather, traffic, and so on.
In particular, necessity for traffic information and service information of public transportation means is constantly increasing with the increment of the number of vehicles in downtown areas, the number of vehicles during holidays, and so on. Accordingly, methods for providing traffic information or bus service information as auxiliary information via satellite, terrestrial broadcast, or mobile communication network are under development. Besides the above methods, a method for providing various application information, for example obstacle information on the road, parking information of a particular area, and the like is also being developed.
Such contents can be provided by different carriers (a carrier means an information transmitter) or by the same carrier. FIG. 1 illustrates a method for providing application information different from each other, for example CTT (Congestion & Travel-Time) information 10 and RTM (Road Traffic Message) information 11 through the same carrier; a data stream transmitted from a single carrier is transferred in such a way that each data frame included in the data stream includes one or more than one type of TPEG message. A service component identifier (SCID) is coded into each service component frame included in a single frame.
Accordingly, a terminal that decodes information organized as above and provided through a single carrier, to show traffic information on the road, uses information decoded from a TPEG-CTT message 10 and uses information decoded from a TPEG-RTM message 11 to show information about a road situation. To show different information, for example bus service information, a TPEG-BSI (Bus Service Information) message related thereto is used.
On the other hand, if the user tries to check parking information while using particular application information, for example congestion information on the road or tries to check service information of long distance transportation means (airplane, express bus, train, etc) while using bus service information, the user has to move from a current service screen on the terminal to a screen providing different service and also has to undergo a menu selection procedure based on a top-down scheme on the new service screen to get desired information. Also, even if the user undergoes the above selection procedure, it becomes cumbersome to find different information associated with particular information that the user has used before. For example, if the user checked service information about an express bus terminal or a bus terminal of an airport through bus service information and then tries to find additional information about express bus service information of the express bus terminal or the airport or airplane service information, the user has to stop using the current bus service information and connect to PTI service of a long distance transportation means to check the additional information (or information decoded from a decoding routine of the PTI service). As a matter of course, the user can know the desired information only after he or she has undergone a cumbersome procedure that requires choosing a desired express bus terminal or airport from the PTI service.